Take a look at your mobile device. Do you see oily fingerprints and lint on the touch screen? Dust and crumbs forming particulate frost in the corners? Is that a hair stuck at the screen’s edge?

Because our electronics are constantly within our grubby grasp, they can get pretty gross. They are taken into public restrooms, handed to runny-nosed toddlers, passed around to share photos and pressed against sweaty skin in gyms. Repeated studies show what accumulates is germy nastiness worse than what is on the bottom of your shoe.

“That devices can be a source of disease transmission is not a subject of debate anymore,” said Dr Dubert Guerrero, an infectious disease specialist at Sanford Health in Fargo, North Dakota, and co-author of a study about the persistence of bacteria on iPads published in November in The American Journal of Infection Control.

So it is a good idea to keep your devices clean, not only to keep from getting sick but also to maintain resale value when it’s time to upgrade. Derek Meister, a technician for the Geek Squad, American retailer Best Buy’s repair and online support service, said. “People don’t want any marks or grime on their devices. The better the condition, the more like new it is, the more money you get on your trade-in.”

A word of warning: Cleaning your device can be tricky, since you don’t want to damage it and manufacturers don’t give you much guidance. It can be done, however, if you’re careful and conscientious.

Dr Guerrero and his colleagues found that regularly wiping down your device with a moist microfibre cloth was sufficient to eliminate many kinds of common bacteria. More enduring and dangerous bacteria like clostridium difficile (which can cause diarrhoea or even inflammation of the colon) and flu viruses may require a sterilising agent like bleach or alcohol, he said.

This is a problem, since Apple on its website officially warns against using “window cleaners, household cleaners, aerosol sprays, solvents, alcohol, ammonia or abrasives” to clean its products and advises instead to “simply wipe the screen with a soft, lint-free cloth to remove oil left by your hands.” Other manufacturers offer similar advice or none at all.

To clean his own mobile devices, Meister at the Geek Squad said he used a 1:1 ratio of 70 percent isopropyl alcohol and distilled water, which together cost less than $4 at most grocery and drugstores. “You want distilled water and purer alcohol so there are fewer chemicals or minerals left behind when the solution evaporates,” he said.

Fill a spray bottle with the diluted alcohol, lightly moisten a lint-free, preferably microfibre, cloth (no paper towels) and gently wipe down the screen and case. Never spray directly onto the device. To clean corners and around ports, use lint-free foam rather than cotton Q-tips.

It’s up to you how obsessively you want to clean your mobile devices, but health and electronics experts advise wiping down your mobile device with a moist microfiber cloth at least daily for basic sanitation and upkeep.

Like your toothbrush, “your mobile device is something you want to clean regularly,” said Dr. Guerrero, the infectious disease specialist. And it is probably not something you want to pass around the table.